Bottom Line:
The results of the controlled medial branch block were not correlated to sex, age, pain duration or work disability but were correlated with patient age (p<0.05).Patient diagnosis with a controlled medial branch block proved to be effective but was not associated with any demographic variables.A three-month follow-up is required to avoid a high number of false positives.

Objectives: To verify the incidence of facetary and low back pain after a controlled medial branch anesthetic block in a three-month follow-up and to verify the correlation between the positive results and the demographic variables.

Methods: Patients with chronic lumbar pain underwent a sham blockade (with a saline injection) and then a controlled medial branch block. Their symptoms were evaluated before and after the sham injection and after the real controlled medial branch block; the symptoms were reevaluated after one day and one week, as well as after one, two and three months using the visual analog scale. We searched for an association between the positive results and the demographic characteristics of the patients.

Results: A total of 104 controlled medial branch blocks were performed and 54 patients (52%) demonstrated >50% improvements in pain after the blockade. After three months, lumbar pain returned in only 18 individuals, with visual analogue scale scores >4. Therefore, these patients were diagnosed with chronic facet low back pain. The three-months of follow-up after the controlled medial branch block excluded 36 patients (67%) with false positive results. The results of the controlled medial branch block were not correlated to sex, age, pain duration or work disability but were correlated with patient age (p<0.05).

Conclusion: Patient diagnosis with a controlled medial branch block proved to be effective but was not associated with any demographic variables. A three-month follow-up is required to avoid a high number of false positives.

f1-cln_69p529: A radiograph in the anterior-posterior view during the controlled medial branch block procedure in one patient, with needles positioned in the medial branches of L3, L4 and L5 (left).

Mentions:
After the VAS was registered, the patient was warned that the test would begin with one injection and was asked to indicate the levels/sites of the most intense back pain. Saline solution (1 ml) was injected at these sites; 10 minutes later, the patient was again asked to indicate the pain intensity on the VAS. If the pain was improved by 50%, a placebo effect was detected and the patient was immediately excluded from the study and did not undergo CMB. If the pain was not improved, CMB was then applied. CMB was performed with a 25-G needle, 90 mm long, through the skin until reaching the medial branch nerves in L2, L3, L4 and L5 in both sides (Figure 1). A dose of 0.5 ml of lidocaine at 2%, without epinephrine, was used in all cases. All procedures were performed by the same surgeon (IDR).

f1-cln_69p529: A radiograph in the anterior-posterior view during the controlled medial branch block procedure in one patient, with needles positioned in the medial branches of L3, L4 and L5 (left).

Mentions:
After the VAS was registered, the patient was warned that the test would begin with one injection and was asked to indicate the levels/sites of the most intense back pain. Saline solution (1 ml) was injected at these sites; 10 minutes later, the patient was again asked to indicate the pain intensity on the VAS. If the pain was improved by 50%, a placebo effect was detected and the patient was immediately excluded from the study and did not undergo CMB. If the pain was not improved, CMB was then applied. CMB was performed with a 25-G needle, 90 mm long, through the skin until reaching the medial branch nerves in L2, L3, L4 and L5 in both sides (Figure 1). A dose of 0.5 ml of lidocaine at 2%, without epinephrine, was used in all cases. All procedures were performed by the same surgeon (IDR).

Bottom Line:
The results of the controlled medial branch block were not correlated to sex, age, pain duration or work disability but were correlated with patient age (p<0.05).Patient diagnosis with a controlled medial branch block proved to be effective but was not associated with any demographic variables.A three-month follow-up is required to avoid a high number of false positives.

Objectives: To verify the incidence of facetary and low back pain after a controlled medial branch anesthetic block in a three-month follow-up and to verify the correlation between the positive results and the demographic variables.

Methods: Patients with chronic lumbar pain underwent a sham blockade (with a saline injection) and then a controlled medial branch block. Their symptoms were evaluated before and after the sham injection and after the real controlled medial branch block; the symptoms were reevaluated after one day and one week, as well as after one, two and three months using the visual analog scale. We searched for an association between the positive results and the demographic characteristics of the patients.

Results: A total of 104 controlled medial branch blocks were performed and 54 patients (52%) demonstrated >50% improvements in pain after the blockade. After three months, lumbar pain returned in only 18 individuals, with visual analogue scale scores >4. Therefore, these patients were diagnosed with chronic facet low back pain. The three-months of follow-up after the controlled medial branch block excluded 36 patients (67%) with false positive results. The results of the controlled medial branch block were not correlated to sex, age, pain duration or work disability but were correlated with patient age (p<0.05).

Conclusion: Patient diagnosis with a controlled medial branch block proved to be effective but was not associated with any demographic variables. A three-month follow-up is required to avoid a high number of false positives.